Reduced graphene oxide (rGO) dispersion was obtained by ultrasonication of rGO powder using dodecanethiol (-SH) as an exfoliating agent. Using thiol chemistry, the gold nanoparticles (Au-NPs) were assembled onto the rGO-SH modified glassy carbon electrode (GCE) which showed a strong binding with the surface of the coated electrode. Furthermore, the GCE/rGO-SH/Au-NPs electrode was used to detect mercury (Hg²⁺) ions in the aqueous solution. When employed as a working electrode, Hg²⁺ ions get adsorbed on the electrode surface which was later electrochemically oxidized by differential pulse voltammetry (DPV) with the enhanced oxidation current at +0.172 V. Moreover, this sensor platform showed linear response for Hg detection from 1–10 μM in phosphate buffer saline (PBS) solution and the detection limit was found to be 0.2 μM (S/N = 3). The characterization of the Au-NPs and rGO-SH films were studied by Fourier-transform infrared spectroscopy (FT-IR), UV-Visible spectroscopy, transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM). The application of the prepared sensor was also demonstrated in detecting mercury ions in tap water samples with satisfactory recovery analysis.

中文翻译：

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选择性检测汞离子的金纳米粒子-硫醇功能化还原氧化石墨烯涂层电化学传感器系统

通过使用十二烷硫醇（-SH）作为剥离剂对rGO粉末进行超声处理，可以降低氧化石墨烯（rGO）的分散度。使用硫醇化学方法，将金纳米颗粒（Au-NPs）组装到rGO-SH修饰的玻碳电极（GCE）上，该电极显示出与涂层电极表面的牢固结合。此外，使用GCE / rGO-SH / Au-NPs电极检测水溶液中的汞（Hg ²⁺）离子。当用作工作电极时，Hg ²⁺离子被吸附在电极表面上，随后通过差分脉冲伏安法（DPV）在+0.172 V下以增强的氧化电流进行电化学氧化。此外，此传感器平台在1-10μM的磷酸盐缓冲盐水中显示出对汞检测的线性响应（ PBS）溶液，检出限为0.2μM（S / N = 3）。通过傅立叶变换红外光谱（FT-IR），紫外可见光谱，透射电子显微镜（TEM）和场发射扫描电子显微镜（FE-SEM）研究了Au-NPs和rGO-SH薄膜的表征。还证明了所制备传感器的应用在自来水样品中检测汞离子方面具有令人满意的回收率分析。